Could spraying particles into marine clouds help cool the planet?

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Engineering  |  Environment  |  Research  |  Science

July 25, 2017







The idea of geoengineering, also known as climate engineering, is very controversial. But as greenhouse gases continue to accumulate in our atmosphere, scientists are beginning to look at possible emergency measures.
A new University of Washington study looks at the idea of marine cloud brightening, which a UW group is investigating as a promising strategy to offset global warming. The strategy would spray saltwater into the air to make marine clouds reflect more incoming solar rays.

Ships crossing the Pacific Ocean emit particles into the clean air that create a seed for marine clouds.NASA

Small-scale tests of marine cloud brightening would also help answer scientific questions about clouds and aerosols, two UW atmospheric scientists say in a paper published in July in the journal Earth’s Future. This dual goal for early-stage geoengineering tests would follow the U.S. National Academies of Sciences’ 2015 recommendation that any tests of geoengineering also yield a scientific benefit.
“A major, unsolved question in climate science is: How much do aerosol particles cool the planet?,” said lead author Rob Wood, a UW professor of atmospheric sciences. “A controlled test would measure the extent to which we are able to alter clouds, and test an important component of climate models.”
Other co-authors are Thomas Ackerman, a UW professor of atmospheric sciences, Philip Rasch at the Department of Energy’s Pacific Northwest National Laboratory and Kelly Wanser at the Ocean Conservancy.

The authors are part of a group that is proposing to spray saltwater over oceans to cause a small increase in the brightness of marine clouds and boost their capacity to reflect sunlight. Doing so could be a short-term measure to offset global warming in a possible future emergency situation. In the meantime, it could also further understanding of the climate system.
One of the biggest uncertainties in climate models ...

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